More than 100,000 patients worldwide have some form of permanently implanted neural interface in the brain. Although effective, these interfaces have several technical limitations that limit the full scope of their clinical efficacy. For severa decades, silicon technology has been touted as the most likely candidate for creating more advanced neural interfaces. Silicon seems to be an ideal and biocompatible material from which to create more advanced interfaces that are miniature, high-density, batch-fabricated and capable of supporting active on-board electronics. Silicon, however, is a brittle material, and while its stiffness allows for easy implant into soft neural tissue, it presents a serious mechanicl mismatch between the implanted device and the soft neural tissue after implant. In this Phase I SBIR Lab to Marketplace proposal, Vulintus LLC will explore the feasibility of a developing a novel class of substrate materials called Shape Memory Polymers (SMP) for the long-term neural implant market. SMP materials are unique in that they offer the traditional technical advantages of silicon (ultra-miniature, batch-fabricated photolithography structures with on-board electronics), but with the added benefit of having much more controllable mechanical and surface chemistry properties. By manipulating the polymer composition, the material can be engineered to undergo a change in modulus of elasticity following implantation. Vulintus will demonstrate an advanced batch fabricated high-yield electrode interface that is up to 100,000 times less stiff than a silicon structure. Vulintus hypothesizes that this paradigm-shifting 'multile modulus' material is ideally suited for extending the long-term functionality of neural interfaces by creating an interface that deforms with brain motion, minimizing tissue damage. The following specific aims are proposed: Aim 1: Demonstrate that differences in material stiffness lead to variations in the immune response for implanted t-e/a SMP neural interfaces. Aim 2: Characterize in vivo functionality of 'optimized' t-e/a SMP cortical electrodes in the rat brain: Preliminary in vitro and in vivo data collected by Vulintus and partners suggest that t-e/a SMP materials are biocompatible and indeed appropriate for invasive neural engineering applications. Vulintus will establish close partnerships with NeuroNexus, a leading commercial electrode manufacturer (see letters of support) to allow us to rapidly take advantage of this emerging technology and gain traction in the commercial market. In Phase I, the feasibility of t-e/a SMP safety and efficacy for long-term functional implants in a rat model will be demonstrated. In Phase II, Vulintus will explore surface chemistry modifications and post-processing steps to allow population and encapsulation of onboard electronics as well as demonstrate and test a product line for use in the commercial animal research market.